With relentless attacks aimed at portraying President Barack Obama's running mate as a governing liability, Republicans hope to raise the stature of GOP vice presidential candidate Paul Ryan, who will debate Biden next month, and score points in closely contested states such as Ohio, Florida and New Hampshire.

"Paul's a close friend, a great family man, and he's got a reformer's heart," Ohio Sen. Rob Portman said at last week's Republican convention in Tampa, Fla. "Contrast this to Joe Biden. Vice President Biden has told people out of work to 'just hang in there' — so much for 'hope and change.'"

As Democrats prepare for their convention in Charlotte, N.C., the GOP is casting the 69-year-old former Delaware senator as a gaffe-prone crazy uncle who's hung around the political scene too long. At the same time, Republicans hopes that sullying Biden's image will help confirm Ryan, the 42-year-old Wisconsin congressman, as a deep thinker destined to take on many of the nation's most pressing challenges.

In an opinion piece published this past week by the Milwaukee Journal Sentinel, Wisconsin Sen. Ron Johnson noted that Biden had said the economy felt like a "a depression" and he accused the vice president of straying from "the Obama campaign talking points."

At the GOP convention, Ohio Gov. John Kasich, who joined Obama, Biden and House Speaker John Boehner for a round of golf last year, recalled Biden telling him he was a "good golfer. And I played golf with Joe Biden, and I can tell you that is not true, as well as all of other things that he says."

"You're crazy, you're absolutely crazy. You're getting as bad as Biden," Eastwood cracked in his made-up conversation with Obama. "Of course we all know Biden is the intellect of the Democratic Party. Kind of a grin with a body behind it."

Biden himself has given as good as he gets.

He often is the loudest voice in the campaign's criticism against the Republican presidential nominee, former Massachusetts Gov. Mitt Romney. Biden led the charge against Romney in a series of speeches in battleground states last spring. He routinely bashes Romney and Ryan's assertions of promoting a "bold" plan on taxes and the Medicare.

"There is nothing gutsy about giving another trillion dollars in tax cuts to millionaires. There is nothing bold about turning Medicare into a voucher system," Biden said in Lordstown, Ohio, on Friday.

Another favorite topic of Biden's has been the administration's rescue of General Motors and Chrysler. Turning to Lordstown's sprawling GM plant, which has rebounded with the production of the compact Chevy Cruze, Biden took Ryan to task for blaming Obama for the closing of his hometown Janesville, Wis., GM plant, and he highlighted Romney's opposition to a taxpayer rescue of the U.S. car companies. The Janesville plant closed in 2008, before Obama's election.

"What they didn't acknowledge is Gov. Romney's position was 'Let Detroit go bankrupt,'" Biden said, referring to the headline on a Romney opinion piece in The New York Times in November 2008.

Democrats say the extra attention serves notice of Biden's abilities as a campaigner, along with his penchant for forming bonds with blue-collar workers through stories about growing up in hardscrabble Scranton, Pa.

He can move an audience with stories about watching his proud yet unemployed father forced to move to Delaware to find work or the death of his first wife and daughter in a car accident shortly after he was elected to the Senate in 1972. Such personal stories make a direct connection with union workers in Ohio or grandmothers in Florida.

"It's an attempt to undermine what they believe is a potent political weapon in the Obama campaign's arsenal," said Democratic strategist Mike Feldman, a former aide to Vice President Al Gore. "If they were ignoring him, that would tell you that they're not that concerned."

Of course, Biden can be prone to commit an unforced error from the podium, handing Republicans an opening.

Most recently, Biden told a Virginia crowd that included hundreds of African-Americans that Romney's plans for Wall Street would put them "back in chains."

In May, Biden said on a Sunday talk show that he was "absolutely comfortable" with same-sex married couples having the same rights as heterosexual married couples. That essentially forced Obama to move forward with his support of same-sex marriage. Biden later apologized to the president for going off-script.

Republican strategist Steve Schmidt, who managed GOP nominee John McCain's 2008 presidential campaign, said Biden was a "formidable politician" and an "effective campaigner" who could garner support among voters prized by both campaigns, including blue-collar workers and Catholics in states such as Pennsylvania and Ohio.

Schmidt warned that the hits on Biden actually could have an unintended consequence heading into to the vice presidential debate set for Oct. 11 in Danville, Ky.

"When you ridicule someone, you're lowering expectations to a point that makes it a lot harder for Paul Ryan to score points," Schmidt said. "There's a downside in that."